Sectional boiler



' A. J. GALLAHER -Oct. 16, 1945.

SECTIONAL BOILER Filed Juli; 1, 1943 2 Sheets-Sheet 1 FIG-Ll;

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Oct. 16, 1945. A J. GALLAHEB 2,386,945 I SECTIONAL BOILER Filed July 1-, 1943 2 sheets-sheet' 2 7 ANDREW J. GALLAHER ATTORNEY Patented Dot. 16, 1945 UNITED STATES PATNT OFFICE SECTIONAL BOILER Andrew J. Gallaher, St. Louis, Mo. Application July 1, 1943, Serial No. 493,146

Claims.

vailing practices.

The present subject embodies certain of the features described and claimed in Patent No.

1,886,387, issued November 8, 1932, to this appli cant, in that embodiments of the present improve-- ments need require no more than two dissimilar types of section for the construction of a boiler characterized by separate intermediate and end sections, irrespective of whether a total odd or even number of sections be employed inthe assembly.

Boilers of the present general type are usually but not exclusively employed for smaller commercial heating installations, and have heretofore been characterized by sections or sectional units of cast-cored construction, the permissive operating pressures of which do not usually exceed values of the order of fifteen to twenty pounds per square inch. Furthermore, sectional boilers embodying castsections have heretofore been prevalently interconnected through the use of push nipples, and the sections held in assembled relation by stay or tie rods necessarily, in a cold boiler, not fully threaded up, whereby to allow for expansion upon heating of the boiler. It 13 not unknown that arrangements of this type involve some degree of hazard because of possible separation of one or more of the sections from adjacent sections in the regions of the push nipple connections. It is accordingly a major general objective of the present invention to provide, first, a boiler which may safely operate Within a range of pressures considerably higher than those permitted in a boiler using cast sections,and further, to overcome the difiiculties referred to by avoidance of push nipple connections, and the utilization of individually removable and replaceable boiler sections interconnected entirely by threaded connections or some equivalent positive type of fitting.

A further and important object of the invention is attained in a considerable increase in fluid capacity of and better flow conditions in each individual section of boilers of the type referred to, by reason of an improved shaping of the several sections.

A further object is attained in a novel constructional boiler, which may be selectively turned end for end. or may be inverted as desired, in accord ance with the total number of boiler sections utilized in assembly, and so that, irrespective of the operative position assumed by the several sections there is preserved an even and constant form of gas or flame passage upwardly through the assembly, from which it results that any end section will exhibit equal efiiciency irrespective of itsinversion or endwise disposition in assembly.

Yet another important objective of the invention is attained in an assembly of sections possible by reason of a unique construction of each section and location of threaded connections therein,

enabling individual remova1 and reinsertion of any section of the assembly, without necessarily disturbing in any way, any of the remaining sections.

Yet another important object of the invention is attained in a unique and highlyjadvantageous construction of the individual sections in improvement of heat-absorbing capacity, in greater strength and ability to withstand higher pressures, and in an improved course of flame or gas travel both between and through the individual sections, as wellas between the sections in assembly.

The foregoing and still further advantages and objects will more clearly appear from the following detailed description of a presently preferred embodiment of the improvements, particularly upon considering the description in connection with the accompanying drawings, in which:

Fig. 1 is a rear elevation of a sectional boiler assembly embodying present improvements, from which a rear cover plate has been removed to show internal construction, and in which a steam header is partly broken away and shown in section to reveal its internal construction;

Fig. 2 is a side elevation, showing certain parts in section, of the assembly of Fig. 1; Fig. 3 is an isometric or perspective View showing a sectional assembly embodying two end sections and a single intermediate section with certain connections but omitting headers;

Fig.4 is an isometric view of one of the paired half elements utilized in forming up one of the individual sections of a welded sheet construction;

Fig. 5 is a plan view of an end closure piece employed in one of the intermediate sections;

Fig. 6 is an end closure member utilized in a welded formof end section;

formed passage-forming sleeve or thimble utilized in constructing the several sections of welded type, and

Fig. 8 is a vertical sectional elevation of fragmentary nature showing a preferred form of fluid outlet connection from the individual sections, and the relation of a header element to the section.

Referring now by characters of reference to the drawings, the assembly in the form selected for illustration and description includes a base In of any suitable form, included therein being a plurality of supporting ledge elements such as H and 12, upon which rest the opposite extremities of the several sections as a primary support therefor. It will be understood that the present improvements are not restricted in usage to a boiler utilizing solely any specific type of fuel, being adapted for any type of gas or oil burner, grate firing, stoker or any other desired form of combustion. Accordingly, one wall of the base portion I is shown as open, to permit insertion of combustion equipment of any selected type, with provision of closures on the job.

Although the present improvements are identified principally with the sections of the boiler,

their arrangement, and the header provisions,

the assembly as a whole preferably includes a housing structure consisting of four vertical closure panels which may be of generally similar construction, shown at M, MA, l and ISA (Figs. 1 and 2) and all of which by preference are readily removable for ease of access to the sectional boiler per se, as for cleaning and service attention. Similarly, atop closure I5 is provided and includes a stack or flue connection H which is or may be of conventional nature.

In the assembly as shown in Fig. 1, it will be seen that five sections are employed or utilized to make up the boiler assembly, these consisting of anend section 28, three intermediate sections 2| and an opposite end section 22. These are conveniently mounted in bridging relation to the ledges or supports II and I2 as shown.

The individual. sections 20,2! and 22 are by preference, when used in high pressure boilers, formed of a relatively heavy gauge sheet metal, in a manner hereinafter more fully described. For the present it may be noted that one side of each end, section and eachside of each intermediate section (as best appears from Fig. 3) is formed to present a, plurality, shown as four, of longitudinal or horizontal, laterally projecting heatabsorbing portions 23, see Fig. 1. These are in the nature of linear protuberances and in transverse section each is of substantially V-shape. Preferably the companion legs of the V-shape portion are disposed at an acute angle to each other, thus forming the said heat-absorbing por-, tions 23. Thus, considering each individual section, there results a passage for fluid having alternately expanded and contracted portions, the walls of the'said passage being spaced apart so that the passage is of substantial depth or thick.- ness at all points. The sections are spaced from each other so as to form zigzag passages between them for hot gas. I

As to general shaping of each section, it will be noted that although there is a marked similarity between the parts of each section lying respectively above and below a horizontal median plane the'rethrough, nevertheless each section is asymmetrically formed with. respect to such median. From this it results that when;

Fig. 7 is an elevation in perspective of a pre-,

the section is inverted, the heat absorbing protuberances are difi'erently presented to the hot gases or flames proceeding upwardly through the spaces between adjacent sections but it will further appear that in assembly, each section is relatively inverted in relation to the adjacent sections; it will further appear that in spite of this facility for inversion of alternate sections in the assembly there is nevertheless preserved a substantial back and forth or zig-zag path for the travel of hot gases from the burner assembly upwardly through the spaces between sections tothe stack ll. This passage, as will later appear from Figs. 1 and 3, is of uniform width throughout, and as will also appear, is unobstructed or unrestricted from the lowermost portions of the sectional boiler through and beyond the sectional assembly, all a will be readily ap parent from a study of Figs. 1 and 3.

In the present construction, by reason of the desirability, at least in certain cases, of utilizing the boiler for relatively high pressure steam, it is desired to avoid the hazards, heretofore noted, of push nipple and tie rod construction. Ac-

cordingly, fluid connections into and out of the several said sections are made entirely by threaded connections or by welding, if desired, in certain zones.

One suitable formof header assembly and connections thereto, is illustrated by Figs. 1, 2 and 8 as including an upper header member 25, traversing the boiler from rear to front but located entirely externally thereof. As will appear from Figs, 1, 2 and 8, the header assembly further includes a lower transverse header member 26, the headers 25 and 26 being connected by a vertical leg 21 so that the three elements 25, 2E and 21 constitute a horizontally disposed U- shaped manifold assembly. Individual fluid con- 40 nections out of each section are preferably made say by welding as by a fillet 32, a short coupling or nipple 39 with internal threads (Fig. 8) into one of the plane end closure plates 3i of the section. The nipple or coupling 38 is connected to a similar short threaded pipe section or nipple 33, the latter into an L 34 and this L, through a further nipple 35 which .may be welded at 35,. is connected into the header element 25. A detachabie connection is provided at 31 say in the form of a threaded union, between nipples 3B and 33. A similar set of connections (not shown in detail) are or may be provided from the lower portion of each section into the bottom header 26, as suggested by the union assembly 48 (Fig. 2). It will now clearly appear that, solely upon breaking the connection as through unions 3'5 and 40, any of the sections 29, 2| or 22 may be pulled ,from the sectional boiler assembly and the same or a substitute section readily inserted without any necessary disturbance whatever of any of the companion sections or their fluid connections. This result is attained partly by reason of the individual connections from each sectioninto the headers, and partly by reason of the substantial width of zig-zag spaces indicated at M between the adjacent sections, all as heretofore described. 7

It will be understood that the present boiler, with only minor modifications if any, but with only minor changes in fittings and accessories, may be utilized selectively as a stem boiler or in a hot water system. In cases where it is desired to employ the assembly in a steam system, the header 25 may be constructed to embody, besides the outer tube, a concentrically disposed internal tube .42 open at its ends, but which extendsat its delivery end, through a baflle element 43 for example into a reducer M, thence into an L 45 into which is connected a takeoff pipe 46. The arrangement of the concentric tubes 42 and 25 will now obviously function as an effective water separator, resulting in issuance of a relatively dry steam through the takeoff pipe 46. This is due'to the fact that steam issuing from the several takeoff connections of the individual sections, thence into the chamber and header '25, will be compelled to change course abruptly through 180 degrees as indicated by the arrows (Fig. l), incident to the passage of the steam through the inner tube 42, thence outwardly into the take-01f pipe 4%. This change in direction will obviously tend to throw out the water particles in the zone just above the riser element 21 of the header assembly, through which such water particles will be returned to the body of water in the several sections of the boiler As to any steam which finds its way to the right hand end of header 25, this will similarly be reversed indirection by the action of bafile 43. Header 25 is preferably given a slight slope, to result in a requisite fall to the left (Fig. 1) thus to return any separated water particles thrown out within the headers 25, back to riser 2! thence to the lower zone of the boiler as described.

Proceeding now to a description of a preferred manner of constructing the individual boiler sections when formed of sheet-and-welded construction, a preferred practice consists in die-forming, as by a press operation, a pair of similar or identical side-forming elements 50, one of which is shown by Fig. 4. Each such element includes a plurality of inwardly hollowed trough-like portions 23 shown as four in number, these preferably being of acute angled construction as above described. One of the legs of each such angulate portion, such as indicated at 52, is substantially horizontal in assembly and the opposite leg 53*, being somewhat longer or wider, is of a trend obliquely upward (or downward), in assembly as will appear from the end views of the section shown by Fig. 1. Along the top margin of each of the half elements 50 is a horizontal top closure portion 54, and along the lower margin is a somewhat correspondingbut narrower bottom closure portion 55. The spaced trough-like portions 23 of the blank 50 are connected by vertical wall elements 55. In forming the blank 59, the elements 56 are each provided with one or a plurality (shown as three) of rectangular openings 50 for a purpose hereinafter appearing.

It will now have appeared that the side portions of each section may consist of a pair of blanks 58, oppositely disposed with their elements 52 and 53 externally projected, and the hollow troughlike portions 23 resulting therefrom, presented inwardly of the section. There now remains the necessity of providing end closures for the twopart structure resulting from the paired elements 56. A suitable form of end closure member is shown by Fig. 5, and generally indicated at 6!. This may be described as a blank formed on each side of a central shank $2 with a plurality of superposed angulate portions 63, now obviously so shaped as to serve in the section as end covers for the several superposed series of angulate portions 52 and 53. There is similarly provided by preference at the time of press-forming the member (3|, an end connection port 54 and a companion end connection port 65. Into each of these is inserted and threaded, or welded as shown by Fig. 8, a suitable nipple or coupling internally threaded for the connections to the headers. In a sheet metal and welded construction of section, the two half elements or blanks as are united as by line or butt welding along the line 56 at the top (Fig. 3) and along the similar line resulting from abutment of margins 61 (Fig. 4) at the bottom of the section. This is followed by insertion of the end blanks 5| each of which is welded in place in a manner now readily apparent, along the several zones of contiguity between the external margins of piece El and the mating internal margins of elements 5t, at each end of the assembly.

The foregoing description has been directed particularly to theconstruction of one of the intermediate sections such as 2|, but applies substantially equally to the construction of either of the end sections 28 or 22, these being identical with each other, or preferably so.

In the case of the end sections however, only a single one of the blanks is utilized, and there is utilized therewith to complete the opposite lateral closure of the section, a substantially planar element It, the latter by preference being provided with angularly outturned marginal projections, one each at top and bottom, and indicated at H and 12., These serve in certain assemblies as abutments for external wall closure elements of the assembly. In this case, as before, a closure is provided at each end of the section, for example as shown by Fig. 6, indicated generally at 73, and characterized by a strip portion i l and angulate portions l5, of now obvious purpose. Connection ports 76 and T! are provided in the same relative location as ports 64 and 65 of blank El. Welding of the end sections includes a top line or butt weld 8G, a corresponding bottom line or butt weld (not shown), a further line of welding 82, and a zig-zag line of weld 83, at each end of the end sections. Nipples or couplings such as 38 may be welded in place in the openings iii and TE as in the intermediate sections.

The construction of the sections as thus far de scribed will result in a thoroughly operative structure of each, but the prime heat-absorbing surface of each section is considerably enhanced and facilities for cleaning the boiler and assei bly considerably improved, as well as certain structural advantages offered by the provision of ports or passages transversely of each section. In an arrangement such as shown, wherein each of the sections is vertically disposed, these passages or ports will be of a relatively short length and horizontal trend. They are indicated in each of Figs. 2, 3 and '7, generally by the numeral 85.

As a convenient means of providing the pas-' sages in both the intermediate and end sections, a sleeve or thimble 85- shown as being of rectangular shaping, is or may be formed of a single element of sheet metal folded with the aid of suitable forming jigs and having its ends united, by a single short line of weld indicated at 86. These thimbles 85, shown as nine in number in each section, are formed so as to bridge the now registering, laterally spaced rectangular openings 60 in each of the blanks 50 or in the end section, located in the blanks 5i] and 73. If desired, each thimble 85 may be made of very slightly greater length than the distance from outside to outside of the companion blanks, and welded securely along each opposite margin 8? of the thimble, to the adjacent metal of the portions 56. It will appear that ample fluid circulation still exists in each section at both ends of and entirely around each of the thimble' members Bi'hence'these members oifer no material obstruction to free vertical circulation in the sections. It is preferable to locate the several passage-forming elements 85, symmetrically with respect to a horizontal median through each section, whereby in the case of sections which are relatively inverted'adjacent those which are relatively upright, there will nevertheless result a series of registering ports or passages extending horizontally through the entire sectional assembly, with obvious advantages in enabling transverse cleaning as by suitable tools, wire brushes or the like, endwise cleaning of the assembly being provided for through the space intervening all parts of the adjacent sections and identified as the zig-zag passages 4!.

Besides affording improved facilities for cleaning, the passages 84 through the several thimble elements 85 materially augment the prime heatabsorbing surface, as noted, but perform a still very important function, particularly in high pressure boilers, since they serve inherently as transverse internal stays, each of the walls of the thimble pieces 85 when Welded into place, obviously serving as tension elements after the manner of tie bolts, stay rods or the like thereby greatly increasing the strength of sections enabling the boiler to carry a higher steam pressure, and to oppose any buckling or distortion effects in any of the sections.

In most installations it has been found necessary only to connect the several sections 20, El and 22, into the headers, through the nipples or couplings 39 at one end of each section. In some special cases however it may be desired to provide connections out of each end of each section, say at top and bottom, in which case the connections shown by Fig. 8 need only be duplicated at the opposite end of each section in now obvious manner. Where single-end connections are employed, the fittings such as nipples 30 at the opposite end, may be provided with suitable caps or plugs, or some thereof provided with connections say for water inlet piping, gauges, etc. These may then be most conveniently connected into the boiler as through tubes 90 and 9! (Fig. 2) for example, through detachable union joints such as 31 and 50 arranged for example as suggested by Fig. 8.

The practice in assembling the several sections is thought to have been apparent from the foregoing detailed description of parts, but it may be noted that, with the base I set up, the assembly of sections is effected by positioning, first, one of the end sections such as '23, then an adjacent relatively upright section 2| followed by an adjacent relatively inverted intermediate section, and so through the series, depending upon the desired number of sections and heat-absorbing surface, until the opposite end section has been installed. Each section is then connected up to the header assemby through the several unions 3'! and 40, and connections completed throughout as described.

It should be noted that each of the intermediate sections should be or may be inverted relative to each adjacent intermediate section, while one of the end sections must be turned end for end and sometimes also inverted, relative to the other end section, from which it results that the boiler, irrespective of total number of end and intermediate sections, need require no more than two dissimilar types of section, and that the total number may be either an even or odd number. It

may further be noted that in case an even total number of sections is utilized, one of the end sections is inverted with respect to the other and also turned end for end, but in case an odd total number of sections is utilized, one of the end sections is merely turned end for end, but without being inverted relative to the other. It will appear that when the sections are assembled as shown by the drawings in either odd or even total numbers, there will always result exactly the same uniform width of back and forth fiame passages, and that these extend clear through all parts of the boiler, entirely unobstructed, from bottom to top and from end to end thereof. From this there results a boiler in which all sections will exhibit equal eliciency in any assembly.

Although the invention has been described by making particular reference to a single preferred embodiment, and the sections have been described in a form preferred for high pressureoperation, as formed up of sheet and Welded construction,

many of the improvements in shaping, design and arrangement are equally applicable toboilers of cast sectional construction. The detail of description is accordingly to be understood solely in an instructive and not in any limiting sense, many variants being possible withinthe scope of the claims hereunto appended.

I claim as my invention:

1. A box-like fluid section for a sectional type boiler including a pair of substantially identically formed sheet metal side portions each characterized by a plurality of linear, horizontal, external protuberances and corresponding internal hollow portions, the two said side portions being metallically united as by welding, at top and bottom, substantially along a vertical plane through the section, and provided with intermediate tie-elements extended through and welded at their ends to the side portions, the section including end closure portions, and the side portions being spaced to provide internally of the section, a passage for fluid having alternately expanded and contracted portions, said spacing further being such that said passage is of substantial width at all points, whereby fluid may circulate fully upwardly and across all parts of the section.

'2. As an article of manufacture, a welded sheet metal section for asectionally assembled boiler, consisting of two identical, opposed hollowed side forming elements welded into assembly and each characterized by a series of horizontal, internally hollow protuberances of substantially V -shape transverse section, and a series of tubular passageforming members extending transversely through the two halves of the section in zones spaced from said protuberances, the passages in said members providing paths of flame travel through the section, the tubular elements serving as stays between the opposite halves of the section and each of said tubular elements being welded at its opposite ends to the opposite halves of the section, the section being characterized by separate substantially planar end closure elements welded into fluid tight connection with said side elements, the side elements being so spaced that there results a fluid chamber in the section having alternately expanded portions resulting from the V-shape protuberances, and intervening contracted portions such that the chamber is of substantial width throughout the height and length of the section, and is coextensive with the height and length of the section except where traversed by said tubular members.

' spaced one above another and 3. In a sectional boiler, a plurality of sections including at leastone intermediate section and a pair of identical end sections, each of said sections being characterized by a series of longitudinal, sectionally angulate protuberances each of horizontal trend, and adjacent sections being relatively inverted so as to present the corresponding protuberances of adjacent sections in vertically spaced relation, whereby to provide a zig-zag flam path of substantial width, extending between and fully coextensive with the lateral surfaces of each pair of adjacent sections from bottom to top of the assembled boiler, and a pair of header elements external to the sections, having individually separable connections to the separate sections.

4. A sectional boiler including a plurality of vertically disposed sections, each of box-like aspect and formed on its opposite sides to provide sharply acutely angular, horizontal tube-like portions, vertically staggered in adjacent sections to provide wide zig-zag paths of flame travel fully through from bottom to top of the assembled boiler, and each section provided with opposite end closures and header connections projected endwise of each section from at least one of the end closures of each thereof, an external header traversing the assembly of sections, and provided with individual threaded pipe connections to'the said several sections, the sections being spaced from each other in assembly by said zig-zag passages, and being individually removable from said assembly merely by breaking the header connection thereto, and without necessarily disturbing any other section of the assembly.

5. In a boiler assembly of sectional construction, a pair of outside fluid sections and a plurality of intermediate sections, each section provided with an inlet and an outlet opening in each end of the section and located equidistantly from a transverse median plane through' the section, each of said sections being similarly but asymmetrically formed with respect to a transverse median therethrough and formed to provide heat-absorbing projections of substantially horizontal trend and acutely angulate cross section, each of the intermediate sections being uniformly constructed and adapted by reason of location of said heat absorbing portions, to enable rotation of any of the sections about a horizontal axis through substantially 180 without altering the locations of end openings with respect to the assembly, and each intermediate section being further adapted to be removed, and added, singly, in any order in the assembly between said outside sections, without disturbing the other sections, all of the said sections being substantially spaced from .each adjacent section in assembly, and having their said heat absorbing portions so formed as to preserve a substantially uniform passage for zig-zag gas travel, through the intersectional spaces, and throughout such spaces fully from bottom to top of the assembly.

6. A sectional boiler assembly comprising a pair of identical fluid-containing sections forming the end closure walls of the sectional assembly, each of said sections being adapted to be used at either opposite end of the assembly, in either a relatively inverted or an end-for-end relation to each other, and an intermediate section, each of said sections being characterized by substantially horizontal acutely angulate tube-like protuberances vertically staggered in adjacent sections to provide a zig-zag path of flame and gas travel between sections, each section having fluid connections adapted for substantial leg and a lower horizontal leg,

alignment, the connections on said intermediate section being equidistantly disposed from the horizontal center line of the section, and the section.

somewhat similarly yet asymmetrically formed on each side of a transverse median therethrough, whereby it is adapted to be used selectively in either upright or inverted position while maintaining the assembly position of said fluid connections, and a header structure separate from and endwise disposed externally of the several sections,

and having external connections of flange type providing for detachable threaded assembly thereto, the headers and sections being so related that, upon severance of said connections, any section may be individually removed from or inserted in the assembly, without disturbance of any other of said sections.

'7. In a sectional steam boiler assembly, a plurality of vertically disposed, individually spaced heating sections, each provided with a pair of header connections endwise projecting from end portions of the section, and a combined header and separator structure of substantially U-shaped form, one leg of which, constituting the separator, consists of an inner tube, an outer tube and a bafile across the outer tube, near the discharge end of said one leg, the outer tube of said leg having an individual connection to the upper portion of each of the several sections of the boiler, and said baiile being arranged to cause the steam to pass through the outer tube, then through the inner tube, said section connections and header structure serving to maintain the sections in assembled relation, the opposite leg of the header structure being provided with individual connections to the lower portions of the several sections, and the header structure including a conduit portion interconnecting the said legs of the header structure.

8. In a sectional steam boiler assembly, a plurality of vertically disposed, spaced heating sections, each provided with a pair of header connections projecting from one of its ends, and a header structure consisting of an upper horizontal both laterally spaced. from and having detachable communication with the individual sections through said header connections, the header structure including a vertical leg serving directly to interconnect the two said horizontal legs, and means providing with and interiorly of the upper horizontal leg, a steam separator therein, adapted to deliver condensate to said vertical leg for return by gravity to the lower horizontal leg.

9. In a sectional steam boiler assembly, a plurality of vertically disposed,spaced heating sections, each provided with a pair of header connections projecting from one of its ends, and a header structure consisting of an upper horizontal leg and a lower horizontal leg, both laterally spaced from and having detachable communication with the individual sections through said header connections, the header structure including a vertical leg serving directly to interconnect the two said horizontal legs, the upper leg being disposed at least slightly above as well as laterally of the uppermost part of the assembly of sections, a separate tube within, along and spaced inwardly of the said upper leg, and baiile means also within the upper leg and coacting with the tube therein to cause a back and forth steam flow in the upper leg for separation of water particles and return thereof through said vertical leg.

10. A fluid section of a type to be vertically disposed in a sectionally assembled boiler, and including opposite side portions identically shaped, each side portion being characterized by longitudinal, linear protuberances of hollow aspect internally of the section, and spaced one above another in each side portion, the side portions bein arranged with their protuberances opposite each other, and said side portions being joined at the top and the bottom, and spaced apart so as to provide a chamber for fluid which, chamber is characterized by alternately expanded and contracted portions, the expanded portions resulting from saidlinear protuberances, the spacing of side portions further being such that the chamber is of substantial width or thickness at all points from bottom to top of the section, and aplurality of elements traversingsaid chamber and joining said side portions inwardly of their margins, the section further including substantially planar end closure portions, marginally joining the said side portions. 1

7 11. In a fluid secti 11 adapted to be vertically mounted in a sectionally assembled boiler, opposite side portions identically formed, each of said side portions being characterized by protuberances forming longitudinal, hollowed, vertically spaced portions presented toward each other, the side portions being joined at the top and bottom, a plurality of open end hollow elements serving to bridge the space between the side portions, and the section including a pair of substantially planar end closure portions, said protuberances being arranged, as to their vertical spacing in the section, and the side portions being sufficiently spaced, so as to provide within the section a chamber for fluid having alternately contracted portions and expanded portions resulting from the vertically spaced protuberances, the spacing of side portions further being such that the chamber is of substantial width or thickness in all zones-from side to side of the section, and the longitudinal protuberances further being so located in the section as to enable inversion, of the section, and after inversion, to provide a diiiering' relation of the protuberances in an assembly of a plurality'of the sections.

l2. In a fluid containing section for use-as one unit of a sectionally assembled boiler, opposite hollowed side portions identically shaped and each characterized by longitudinal, interiorly hollow projections spaced one above, another, a pair of end closures connecting, the side portions, a pair of header connectionsnearthe opposite ends of at least one endclosure, projectingtherefrom in a direction endwise of the section, the said side portions being spaced apart to provide internally of the section a fluid chamber having alternately expanded and contracted portions resulting from the said spaced longitudinal projections, and further spaced sufiiciently that the chamber is of substantial Width or thickness in all zones from-bottom to top and from end toend of the section, and a plurality of vertically and longitudinally spacedbridging elements internally of the section and secured to said side portions thereof in zones intervening said hollow projections.

13. A fluid containing section for a boiler of sectional type in which the sections are vertically disposed, each section including a pair of opposite, substantially similar side portions internally hollowed to provide a series of vertically spaced, longitudinal, trough-like portions of generally angular section, and end closure portions, one of said end closure portions being provided with a header connection nearits upper end'and a similar header connection near its lower end, the header connections being equidistantly spaced from a horizontal median through the section whereby to enable inversion of the section in assembly, while preserving identical locations of the respective header connections, the said side portions of the section being spaced apart to an extent to form a chamber for fluid within the section, characterized by alternately contracted and expanded zones resulting from said longitudinal trough-like portions, and the spacing of side portions further being such as to provide a substantial Width or depth of the chamber in all zones of the section from bottom to top and from end to end thereof, and a plurality of stay elements bridging the space between the side portions and projecting depthwise of the section, the chamber in thesection being otherwise free of obstruction to free fluid flow inany direction between its various portions.

14. A fluid containing section for a boiler of sectional type, in which the sections are vertically disposed, each section being formed as a fabricated box-like structure of sheet metal including a pair of opposite, substantially identical side portions internally hollowed to provide a series of longitudinal trough-like portions spaced one above another in the section, and end closures, one of which is provided with a header connection near its upper end and a similar header connection near its lower end, the header connections being equidistantly spaced from the horizontal median plane through the section whereby to enable inversion of the section in assembly, While preserving identical locations of the respective header connections in assembly, the trough-like portions being so disposed relative to each other and to a horizontal median through the section that, upon inversion of the section, said trough-like portions occupy diiierent vertical positions in the assembly or" a plurality of the'sections in a boiler, the said side portions of the section being spaced apart sufi'iciently to provide a fluid chamber in the section characterized by vertically alternate expanded and contracted portions, the relatively expanded portions resulting from said trough-like hollow portions, the spacing of the side portions further being such that the chamber Withinthe section is of substantial width or thickness at all points from top to bottom and from end to end of the section, whereby to provide for free fluid flow in any direction within the section and fully over its area, said longitudinal trough-like portions being so formed and located on the section that, upon relative inversion of adjacent sections there results a passage therebetween for gas or flame travel of zig-zag trend, and of substantially uniform width, from bottom to top of the assembly and along each section from end to end thereof.

15. In a boiler assembly of sectional construction, a pair of outside fluid sections and a plurality of intermediate sections, each section provided with an inlet and an outlet opening in at least one end of the section, and located equidistantly from a transverse median plane through the section, each of said sections being similarly but asymmetrically formed with respect to a transverse median therethrough and formed to provide heat absorbing projections of substantially horizontal trend and of a generally angulate cross section, each of the intermediate sections being uniformly constructed and adapted by reason of location of said heat absorbing projections, to enable rotation of any of the sections about a horizontal axis through substantially 180 degrees without altering the locations of end openings with respect to the assembly, and each intermediate section being further adapted to be removed and added singly in any order in the assembly between said outside sections without disturbing the other sections, each of said sections being formed of opposite, substantially spaced wall portions in at least one of which is formed the said heat absorbing projections, said projections being vertically spaced from each other and the spacing of the opposite wall portions such as to provide a fluid chamber in each section having alternately contracted and expanded portions, the latter resulting from said heat absorbing projections, the Wall portions fur- ANDREW J. GALLAHER. 

